Steam boiler furnace



(No Model.) 8 2 Sheets-Sheet 1.

J. 85 J. R. SCOTT. STEAM BOILER FURNACE. No. 498,580. Patented May 30, 1893.

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WITNESSES! INVENTORS W W M M 2 WW;

UNITED STATES PATENT OFFICE.

JAMES SCOTT AND JAMES R. SCOTT, OF GRANTON, SCOTLAND.

STEAM-BOILER FURNACE.

SPECIFICATION forming part of Letters Patent No. 498,580, dated May 30, 1893. Application filed September 13,1892. Serial lilo-445,787. (N model.) Patented in England October 8, 1891, No. 17,116-

To aZZ whom it may concern.-

Be it known that we, JAMES SCOTT and JAMES ROBERT SCOTT, subjects of the Queen of Great Britain and Ireland, and residents of Granton, in the county of Mid-Lothian, Scotland, have invented new and useful Improvements in Steam-Boiler Furnaces, (for which we have obtained British Letters Patent, dated October 8, 1891, No.17,116,) of which the following is a specification.

Thisinvention has for its objects to improve the construction of steam-boiler furnaces and parts connected therewith, to prevent or diminish smoke, and to secure economy.

In carrying out the invention each furnace is of the internal kind, being formed within a cylindrical shell or tube, or within an internal fire-box of any suitable shape. The main grate bars consist of tubes placed transversely and inclined. The inner end of the furnace space above the bars is closed by a brick partition and the fire-gases proceed from the fuel on the bars down through between the bars, and onward under the end partition into the flue beyond. In boilers of the marine type and others we employ perforated metal plates or ordinary grate bars placed horizontally beneath the water tube grate bars in a position such that sufiiicient air can pass beneath them and thence up through them to insure the complete combustion of any inexhausted fuel which may drop through the water tube bars above. The grate bar water tubes com municate at both ends of each with the water spaces of the boiler and by their inclination insure a Vigorous circulation of water.

Figure 1, of the accompanying drawings is an end elevation with one half in vertical section, and Fig. 2, is a vertical section as at right angles to Fig. 1, of an ordinary boiler of the marine type showing how the improvements are to be applied.

In the drawings the same reference letters are used to mark the same or like parts wherever they are repeated.

As shown in the drawings each furnace, A, is of the internal kind being formed within a cylindrical shell or tube, B. The grate bars consist of tubes, 0, placed transversely and inclined. The inner end, D, of the furnace space, A, above the bars, 0, is closed by a brick partition, E; and the fire gases proceed from the fuel on the bars, 0, down through between the bars and onward under the end partition, E. A set of ordinary grate bars is placed beneath the water tube bars, O, in a horizontal position leavinga suflicient space, H, between them and the furnace bottom to permit air to pass between them upward into the space between the upper and lower bars completely consuming any inexhausted fuel which may happen to fall from the fire-grate bars, 0, above. The flow of air between the bottom of the water tube fire bars, 0, and the lower bars, F, can be regulated bya door, .I, movable on hinges on the furnace front plate, K. Air enters the space. above the water tube bars, 0, round the edges of a door, L, hinged to brackets on the front plate, K. The arrows in Fig. 2,'indicate the directions of the air and gas currents. The grate bar water tubes, 0, communicate at both ends of each with the water spaces, S, of the boiler and by their inclination insure a vigorous circulation of the water. Each tube or tubular bar, 0, is made up of two lengths, O, G, united by a screwed thimble coupling, T, andthe outer ends, which project through holes in the furnace shell are screwed into the holes and are fixed byscrew nuts, W. The said nuts, W, are screwed on both ends of each tubular bar, 0, both on the outside and inside of the furnace shell.

The construction of the tubular bars, 0, as described facilitates their fixing in or removal from new or existing boilers. The said tubular bars, (3, by their construction and fixing, also contribute materially to the strength of the furnace shell.

What we claim as our invention is 1. In a steam boiler furnace, the combination of a tube or shell within the boiler, an upper set of grate bars consisting of inclined water tubes transversely arranged, whereby the injurious efiects of expansion of the tubes is reduced to a minimum, a partition closing the inner end of the space above the water tube bars, compelling the gases from the fuel on said bars to pass down between them, a

through the shell from the inside of the furnace.

In testimony whereof we have signed our names to this specification in the presence of 15 two subscribing witnesses.

JAMES SCOTT. JAMES R. SCOTT.

Witnesses:

EDMUND HUNT, DAVID FERGUSON. 

